Network coding based multiple-access channel with a dedicated-relay versus cooperative communications

The idea of relaying and cooperative communications has been proved to be one of the most efficient ways to counter the detrimental effects of the wireless channel used for communications. In this paper, we analytically evaluate network coding based multiple-access channel using a dedicated relay. As a performance measure, we use outage probability and another metric extensively used in multiple antenna systems called diversity-multiplexing trade-off. Later we compare its performance with cooperative communications utilizing network coding. With analytic results we show that cooperative transmission exhibits better gain than multiple-access channel using a dedicated relay in terms of diversity gain. We also derive and compare both of the schemes in terms of diversity-multiplexing trade-off and the results re-validates our argument that cooperative communications leads multiple-access channel utilizing a dedicated relay in terms of diversity gain. In addition, extra hardware needed for dedicated relay is also saved by using the idea of cooperative communications, where the transmitting users themselves are made to act as relays to help each other.